How does an unloader work?

H

hotwaterwisard

Guest
What is an Unloader? It is a mechanical device that switches water from one place to another. It "unloads" the pressure from the head of the pump. There are two types. #1 is the most common. A pressure sensitive unloader. The work is done by the pressure. Sometimes they call it a lock up unloader or a pressure unloader. It holds the pressure in the line. When you pull the trigger it has a surge of pressure and levels off. The pressure overcomes the tention on a big spring when the pressure is higher than the set limit. The nut or Knob on the top of the spring sets the limit. If you set it too high it will cause a big spike in pressure and dammage the pump and burner coils and you could pop a hole in your pressure hose. The other style or #2 is a flow sensitive unloader it uses water "flow" to work. When you shut off the gun the flow stops and it pushes a plunger inside to switch the flow from one place to another. When you let go of the trigger it relieves the pressure off of the hose and coils and it is safer than the other one. When you pull the trigger it takes time for the pressure to build up. Why do you need an unloader? The pump is a positive displacement pump. What that means is it keeps putting out pressure as long as it is running. If you stop the water by letting go of the trigger the pressure keeps building until something explodes. It is water it does not now any better. So when you add an unloader it gives the water someplace to go, so your pump does not blow up. It usually bypasses in a circle into the inlet of the pump. The best place for the bypass to go is tnto a big tank. The water going in a circle gets hot and causes dammage after a while.

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Hotwaterwizard@aol.com John DeRosa
 
H

hotwaterwisard

Guest
Originally posted by hotwaterwisard:
What is an Unloader? It is a mechanical device that switches water from one place to another. It "unloads" the pressure from the head of the pump. There are two types. #1 is the most common. A pressure sensitive unloader. The work is done by the pressure. Sometimes they call it a lock up unloader or a pressure unloader. It holds the pressure in the line. When you pull the trigger it has a surge of pressure and levels off. The pressure overcomes the tention on a big spring when the pressure is higher than the set limit. The nut or Knob on the top of the spring sets the limit. If you set it too high it will cause a big spike in pressure and dammage the pump and burner coils and you could pop a hole in your pressure hose. The other style or #2 is a flow sensitive unloader it uses water "flow" to work. When you shut off the gun the flow stops and it pushes a plunger inside to switch the flow from one place to another. When you let go of the trigger it relieves the pressure off of the hose and coils and it is safer than the other one. When you pull the trigger it takes time for the pressure to build up. Why do you need an unloader? The pump is a positive displacement pump. What that means is it keeps putting out pressure as long as it is running. If you stop the water by letting go of the trigger the pressure keeps building until something explodes. It is water it does not now any better. So when you add an unloader it gives the water someplace to go, so your pump does not blow up. It usually bypasses in a circle into the inlet of the pump. The best place for the bypass to go is tnto a big tank. The water going in a circle gets hot and causes dammage after a while.




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Hotwaterwizard@aol.com John DeRosa "If I Can't fix it no one can."
 

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